package com.lzhpo.common.realm;

import org.apache.shiro.SecurityUtils;
import org.apache.shiro.cache.Cache;
import org.apache.shiro.cache.CacheManager;
import org.apache.shiro.session.Session;
import org.apache.shiro.session.mgt.DefaultSessionKey;
import org.apache.shiro.session.mgt.SessionManager;
import org.apache.shiro.subject.Subject;
import org.apache.shiro.web.filter.AccessControlFilter;
import org.apache.shiro.web.util.WebUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.Serializable;
import java.util.Deque;
import java.util.LinkedList;

/**
 * @author lijin
 */
public class KickoutSessionControlFilter extends AccessControlFilter {

    private static Logger logger = LoggerFactory.getLogger(KickoutSessionControlFilter.class);

    private String kickoutUrl; //踢出后到的地址
    private boolean kickoutAfter = false; //踢出之前登录的/之后登录的用户 默认踢出之前登录的用户
    private int maxSession = 1; //同一个帐号最大会话数 默认1

    private SessionManager sessionManager;
    private Cache<String, Deque<Serializable>> cache;

    public void setKickoutUrl(String kickoutUrl) {
        this.kickoutUrl = kickoutUrl;
    }

    public void setKickoutAfter(boolean kickoutAfter) {
        this.kickoutAfter = kickoutAfter;
    }

    public void setMaxSession(int maxSession) {
        this.maxSession = maxSession;
    }

    public void setSessionManager(SessionManager sessionManager) {
        this.sessionManager = sessionManager;
    }

    public void setCacheManager(CacheManager cacheManager) {
        this.cache = cacheManager.getCache("shiro-kickout-session");
    }

    @Override
    protected boolean isAccessAllowed(ServletRequest request, ServletResponse response, Object mappedValue) throws Exception {
        return false;
    }

    @Override
    protected boolean onAccessDenied(ServletRequest request, ServletResponse response) throws Exception {
        Subject subject = getSubject(request, response);
        if (!subject.isAuthenticated() && !subject.isRemembered()) {
            //如果没有登录，直接进行之后的流程
            return true;
        }

        Session session = subject.getSession();
        // ShiroUser user = (ShiroUser) subject.getPrincipal();
        AuthRealm.ShiroUser user = (AuthRealm.ShiroUser) SecurityUtils.getSubject().getPrincipal();
        String username = user.getloginName();
        Serializable sessionId = session.getId();

        //读取缓存   没有就存入
        Deque<Serializable> deque = cache.get(username);
        if (deque == null) {
            deque = new LinkedList<Serializable>();
            cache.put(username, deque);
        }

        //如果队列里没有此sessionId，且用户没有被踢出；放入队列
        if (!deque.contains(sessionId) && session.getAttribute("kickout") == null) {
            deque.push(sessionId);
        }

        //如果队列里的sessionId数超出最大会话数，开始踢人
        while (deque.size() > maxSession) {
            Serializable kickoutSessionId = null;
            if (kickoutAfter) { //如果踢出后者
                kickoutSessionId = deque.removeFirst();
            } else { //否则踢出前者
                kickoutSessionId = deque.removeLast();
            }
            try {
                Session kickoutSession = sessionManager.getSession(new DefaultSessionKey(kickoutSessionId));
                if (kickoutSession != null) {
                    //设置会话的kickout属性表示踢出了
                    kickoutSession.setAttribute("kickout", true);
                }
            } catch (Exception e) {//ignore exception
                e.printStackTrace();
            }
        }

        //如果被踢出了，直接退出，重定向到踢出后的地址
        if (session.getAttribute("kickout") != null) {
            //会话被踢出了
            try {
                subject.logout();
            } catch (Exception e) { //ignore
            }
            saveRequest(request);

            HttpServletRequest httpRequest = WebUtils.toHttp(request);
            if (isAjax(httpRequest)) {
                logger.debug("当前用户已经在其他地方登录，并且是Ajax请求！");
                HttpServletResponse httpServletResponse = WebUtils.toHttp(response);
                // 向http头添加 状态 sessionstatus
                httpServletResponse.setHeader("sessionstatus", "kickout");
                // 向http头添加登录的url
                httpServletResponse.addHeader("loginPath", kickoutUrl);
//                httpServletResponse.sendError(ShiroFilterUtils.HTTP_STATUS_SESSION_EXPIRE);
                return false;
            } else {
                request.setAttribute("user_status", "300");
                request.setAttribute("message", "您已经在其他地方登录，请重新登录！");
                request.getRequestDispatcher(kickoutUrl).forward(request, response);
                return false;
            }
        }

        return true;
    }

    public  boolean isAjax(HttpServletRequest request) {
        String param = request.getHeader("X-Requested-With");
        if ("XMLHttpRequest".equals(param)) {
            return true;
        } else {
            return false;
        }
    }


}
